I'm carrying out some daylight calculations for a building which has an exterior shading screen. I have modelled this as a component block, setting its transmittance to 0.20. However, in the daylighting results I get that the zones in which this screen is placed the illuminance level is 0 lux. I have tried changing the transmittance to 0.80 and 1 and the result is the same. It seems that the program assumes that the component block is opaque.